Gold Nanoshells-Based Lateral Flow Assay for the Detection of Chagas Disease at the Point-of-Care

Abstract

Chagas disease is a neglected parasitic infection and a major public health problem in the Americas. It remains underdiagnosed in the United States and internationally due to the lack of affordable testing and disparities in healthcare, particularly for those most at risk. We describe a proof-of-concept lateral flow immunoassay employing a recombinant Chagas multiantigen conjugated to gold nanoshells (AuNS) to detect circulating human anti-Chagas IgG antibodies. This is one of the first lateral flow immunoassays to capitalize on the larger surface area of AuNS compared with nanoparticles that can help amplify low-magnitude signals. Results were compared with 42 positive and negative Chagas serum samples, of which a subset of 27 samples was validated against an ELISA (Hemagen®). The sensitivity and specificity of our assay were 83% and 95%, respectively. These results suggest that an AuNS-based rapid testing for Chagas disease could facilitate in-field screening/diagnosis with a performance comparable to commercial methods.

Tailored Ultrastable Core–Shell Au@Ag Nanoparticles for Enhanced Colorimetric Detection in Lateral Flow Assays

“…8,12 Strategy based on low-density material cores, such as silica, embedded in a metallic shell, allows to overcome this size limitation. 13,14 An alternative approach consists of modification of the composition of the nanoparticles. Notably, silver nanoparticles possess superior intrinsic optical properties owing to their low ε i (see eq 1).…”

“…However, in practice, this strategy is rather limited because the nanoparticle size must be inferior to 100 nm for most applications to mitigate issues such as settling or aggregation. For instance, Li et al reported that AuNPs larger than 100 nm are unsuitable for LFA, as gravity dominates their behavior, leading to reduced sensitivity. , Strategy based on low-density material cores, such as silica, embedded in a metallic shell, allows to overcome this size limitation. , An alternative approach consists of modification of the composition of the nanoparticles. Notably, silver nanoparticles possess superior intrinsic optical properties owing to their low ε i (see eq ).…”